1. Field of the Invention
The present invention relates to technology for relaying data transmitted and received between communication devices.
2. Description of the Related Art
By using technology such as a Virtual Private Network (VPN) and tunneling, data transmitted from a terminal located inside a private network can be relayed to a terminal located in another private network via the Internet. For example, by establishing a connection between a Local Area Network (LAN) of a headquarter office and a LAN of a branch office via the VPN, data can be relayed between terminals connected to different LANs via the Internet.
According to known technology, data is relayed between local systems connected via the Internet. According to this technology, each terminal located within a local system accesses a relay server on the Internet to establish a Transmission Control Protocol (TCP) connection, and uses the established TCP connection to transmit and receive data between the local systems.
By using the technology of the VPN and the tunneling, data can be transmitted and received between different LANs connected via the Internet. However, such technology provides a system which is constructed by a fixed setting. That is, a relay device provided on the Internet between the LANs carries out a fixed connection setting between the LANs. Therefore, there is no problem when a VPN connection is preferably established constantly between a headquarter office and a branch office of a company, for example. However, the above-described technology cannot support a case in which a connection is to be established dynamically between different private networks.
The technology such as the VPN is basically technology for establishing a connection between networks, for example, between a LAN and a LAN, and is not technology for establishing a connection between individual terminals. Therefore, the technology such as the VPN is technology for enabling communication to be carried out between networks in which the VPN is developed as an infrastructure, and is not technology for supporting a case in which an individual personally demands a communication with a specific network.
Meanwhile, when constructing a system in which a connection is established between networks in response to a request from individual terminals, performance of a relay device may decrease due to a fact that resources may become insufficient when a plurality of connections are generated according to the request from terminals.